الفهرس 
IntrodactionOnly 14 pages are availabe for public view
 |  | from | 85 |  |  |
| | | from | 85 | | |
Abstract
Objectives: the purpose of this study was to compare the cyclic fatigue (Race, TRU shap ,XP-Endo) in the cyclic fatigue testing device ( custom-made). Methods: sixty of niti rotary files which dicided in to three groups each group 20=no which is (XP-Endo shaper system , Race and TRU shap Theses files tested with special designed custom-made cyclic fatigue testing device , The device consists of mainframe steel block containing the artificial canals, and a mobile support for the electric hand piece that allow precise and simple reproducible placement of each instrument inside the artificial canal ensuring three dimensional alignment and positioning of the instrument to the same depth. Results: XP-Endo shaper showed significantly the highest fatigue resistance followed by TRU shape instruments then Race instruments. Conclusion: Within the limitations of the methodology it could be concluded that the XPS instruments had improved the resistance to cyclic fatigue. The improved alloy properties of XPS (Max Wire) and smaller taper size might enhance the fatigue resistance compared with the other tested instruments. Moreover, TRUShape instrument with heat treatment in shape design had improved cyclic fatigue resistor compared to Race instrument manufactured from conventional NiTi alloy.